Grappling With VAP

Respiratory care providers are on the frontline of a war with many enemies – multi-drug-resistant bacteria on a march to colonize and infect human lungs. Patients on mechanical ventilation are most likely to fall victim to these bacterial invaders, which cause ventilator-acquired pneumonia (VAP) and other ventilator-associated events (VAE).

While once the “super power’ collectively known as antibiotics could wipe out the intruders; today, effective care is proving more difficult. A steady increase of VAP-inducing organisms for which there is no medication and no therapy is a problem in expansion mode.

“We only know the tip of the iceberg about bacteria. While we know the usual culprits when it comes to VAP, there are lots of bacteria that we cannot even identify with our conventional culturing mechanisms,” explained Amesh A. Adalja, MD, FACP, FACEP, board-certified in infectious disease and critical care medicine, of the University of Pittsburgh. “What we are seeing is more and more discovery of bacteria, simply because our detection systems are getting much more sophisticated. Most bacterial species have not yet been identified by humans.”

Rapid Bacterial Evolution
In addition to the expanding body of bacterial suspects, those that are known to medical science are rapidly evolving. Adalja noted that in the course of two or three years, he has seen bacteria resistant to only one or two antibiotics become resistant to all antibiotics.

“Bacteria have a very fast generation time and they are evolutionarily-adapted to resist antibiotics because they themselves use antibiotics against each other in the environment,” he explained. “So they’ve ‘seen’ almost everything that we can throw at them and they have genetic mechanisms that can be turned on – in exchanges between themselves – in order to resist these antibiotics and survive.”

In what sounds like a science fiction horror film scenario, the populations of these bacteria grow in “Blob”-like volume. “They multiply very fast,” said Adalja. “So the selective pressure we put on them with antibiotics is something they can more easily overcome than any other species on the planet.” In fact, he proclaimed them “the most successful species on the planet; they’ve been on the earth billions of years longer than humans.”

RTs can best serve their patients by understanding the connection between ventilation and bacteria exposure, and by practicing advocacy on their patients’ behalf.

Conduit for Infection
“When a patient is on a respiratory tube from a ventilator, it creates a straight pathway into the trachea, the lungs – the entire respiratory system,” said Adalja. “This allows organisms to bypass normal defense mechanisms since ventilated patients can’t cough out bacteria, can’t spit.” Additionally, patients who are in ICU are routinely confronted with lurking bacteria that is much more highly resistant to medication – more so than would be found in a normal community setting. It’s something of a perfect storm. “Patients are in a setting where they are exposed to multi-drug-resistant bacteria, plus there is a conduit for bacteria to exploit and invade patient lungs,” said Adalja.

In addition to the fact that these bacteria render VAP an untreatable disease in some circumstances, the economic burden of VAP and other VAE is enormous. VAP alone costs millions of dollars every year; the CDC estimates cost per infection ranges from $14,000 – $29,000 and the overall estimated total cost in the U.S. ranges from $0.8 billion – $1.5 billion annually. And even though VAP bundles in use in facilities throughout the U.S. have helped decrease the number of infections, recent research shows that VAP is still asserting its prominence. In 2011, a CDC healthcare-associated infection (HAI) survey conducted in a large sampling of U.S. hospitals determined that “on any given day, about 1 in 25 hospital patients has at least one healthcare-associated infection.” The most common HAI was pneumonia – 157,500 cases (21.9% of all HAI) were reported in the 2011 survey. The full report, published in May 2014 in the New England Journal of Medicine, also noted that device-associated infections (central-catheter-associated bloodstream infection, catheter-associated urinary tract infection, and VAP), “which have traditionally been the focus of programs to prevent HAIs, accounted for 25.6% of such infections.”

Proactive Measures
It is universally acknowledged that mechanical ventilation is a life-saving intervention and an essential tool in the respiratory arsenal. “But what respiratory care providers need to assess in a real-time basis is how quickly a patient can be extubated from the ventilator,” said Adalja. “Each day that patients are on a ventilator, their chances of getting VAP increase. The quicker you can get that tube out, the better.”

Adalja said RTs need to be proactive in advocating for a timely weaning from ventilators. “For example, suppose a patient comes back from the OR late at night and a decision is made to let them remain on the ventilator all night, then extubate them in the morning. That is the wrong decision; it increases risk of VAP and a possible fatal illness. Respiratory therapists must advocate a move to extubation as soon as possible – even if it is 1 or 2 in the morning,” said Adalja. “That is such an important thing an RT can do – push for early extubation, when feasible. The other thing they must do, of course, is follow explicit hand hygiene, and follow infection control procedures to the letter because the patient in the room next door might have a multi-resistant bacteria and you don’t want to spread it to a patient who doesn’t already have it.”

New drug delivery systems may be one hopeful weapon in the fight against VAP-causing bacteria. While medications for VAP are usually delivered intravenously, inhaled antibiotics may take a more direct route – the same one used by invading bacteria.

“One of the advantages is that the concentration of medication that is delivered to the lungs can be very high – higher than achieved when you give something intravenously,” said Adalja. “The inhaled antibiotic is being delivered right to the site of infection – the lungs. With intravenous delivery, you can never be sure of the exact amount of medication reaching the infection site – it can vary from person to person. You don’t have that worry with inhaled antibiotics. We are still not certain about the optimum delivery – perhaps some inhaled and some intravenous will prove to be the best tactic. We still have much to learn.”

Valerie Neff Newitt is on staff at ADVANCE. Contact:

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